Overview

Free Androgen Index Test

also known as:
androgen index

What is Free Androgen Index Test?

Free androgen index (FAI) is a ratio obtained after a blood test that detects the testosterone levels. The test is used to determine if an individual has abnormal androgen levels. The test measures the levels of total testosterone, free testosterone and a protein called steroid hormone binding globulin (SHBG). The free androgen index measures the testosterone in the blood and compares it with the total testosterone and SHBG in the body. The male hormones called androgens are produced in both men and women. Women with increased androgen levels may be at risk of a condition called polycystic ovarian syndrome (PCOS).

Preparation for Free Androgen Index Test

It is recommended that you wear a sleeveless or short-sleeved shirt or a full-sleeved shirt with sleeves rolled up to enable easy withdrawal of blood from your arm.
No test preparation is required. There are no dietary restrictions that you have to follow before the test. Certain medications that you are currently taking may affect the test results. So, make sure to inform your doctor regarding all the medications, vitamins, herbs and supplements you are taking. In case the blood withdrawn is to be used for further tests, your doctor will inform you the necessary preparations in prior.

Uses of Free Androgen Index Test

The free androgen index is used to detect the androgen level in the blood. Both men and women synthesize the male sex hormones called androgens. The test results may vary by age, gender and overall health of the individual. The normal values of FAI range between 30 and 150 in men. If the level is below 30, it indicates a possibility of testosterone deficiency.
In males, if the total testosterone level is below 200 ng/dL, it may be indicative of hypogonadism which is an androgen deficiency that causes testosterone levels to drop.
In women the normal range is between 7 and 10. Excess androgen levels will cause increased body hair growth which may be indicative of PCOS.

Procedure for Free Androgen Index Test

A few millilitres of blood sample is required for this test. This will be obtained directly from your arm.
The insertion site is prepared for the withdrawal of blood.
An elastic band is wrapped around your arm to make the veins swell with blood.
The site to be injected is cleansed with antiseptic.
The needle is inserted into the vein and a tube attached to the needle is then filled up with blood.
A gauze pad or cotton ball is placed over the punctured area as the needle is removed.
The sample is transferred to the laboratory for further examination.

Limitations of Free Androgen Index Test

The free androgen index is intended to give a guide to the free testosterone level, but it is not very accurate.